sentence structure vs phrase structure

sentence structure and phrase structure both are nouns.

Word	Noun	Adjective	Verb	Adverb
sentence structure	Yes	No	No	No
phrase structure	Yes	No	No	No

As nouns, sentence structure and phrase structure are synonyms defined as:

sentence structure and phrase structure: the grammatical arrangement of words in sentences

Other synonyms of sentence structure include syntax.

sentence structure (noun)	phrase structure (noun)
the grammatical arrangement of words in sentences	the grammatical arrangement of words in sentences